Trifluoroacetic acid → [(3aR,5R,6S,7R,7aR)-6,7-diacetyloxy-2-(2-phenylmethoxyethylamino)-5,6,7,7a-tetrahydro-3aH-pyrano[3,2-d][1,3]thiazol-5-yl]methyl acetate

Participants

Reaction Steps

To a solution of (2S,3R,4R,5S,6R)-6-(acetoxymethyl)-3-isothiocyanato-tetrahydro-2H-pyran-2,4,5-triyl triacetate (9.8 g, 25 mmol) in dichloromethane (100 mL) was added 128 (4 g, 26 mmol) at 0° C. After stirred for 2 hours, trifluoroacetic acid (15.4 g, 159 mmol) was added. The resulting solution was stirred for 12 hours at room temperature, then quenched with ice-water (200 mL) and neutralized by the addition of NaHCO3 (26 g, 318 mmol). The organic layer was separated and the aqueous layer was extracted with dichloromethane (3×100 mL). The combined organic layer was washed with brine (2×100 mL), dried over anhydrous sodium sulfate, and concentrated under vacuum to give a residue, which was purified by silica gel column, eluted with 10%-50% ethyl acetate in petroleum ether to afford 129 as a white syrup (9.8 g, 77%). (ES, m/z) [M+H]+ 481.0; 1H NMR (300 MHz, CDCl3) δ 7.31-7.38 (m, 5H), 6.24 (d, J=6.3 Hz, 1H), 5.41-5.43 (m, 1H), 4.94-4.98 (m, 1H), 4.55 (s, 2H), 4.34-4.37 (m, 1H), 4.14-4.16 (m, 3H), 3.83-3.87 (m, 1H), 3.64 (t, J=5.4 Hz, 2H), 3.53 (t, J=5.1 Hz, 2H), 2.12 (s, 3H), 2.10 (s, 3H), 2.09 (s, 3H).

Provenance & Evidence